This invention is related to a photographic process for the preparation of colloid relief images, and more particularly with the utilization of colloid insolubilizing developing agents in conjunction with a non-hardening silver halide emulsion.
It is of course well known in the art to utilize developing agents to insolubilize colloidal materials, e.g., gelatin, in a silver halide emulsion. Typically, in the employment of this hardening reaction, a tanning developer such as catechol is utilized to develop an exposed silver halide colloidal emulsion, after which the unexposed areas may be washed away utilizing warm water, to thereby obtain a photographic image or resist of the hardened or tanned colloid.
This mechanism for obtaining a photographic resist, however, has typically not been available when the colloidal materials are removed from the site at which development occurs, such as for example in a colloidal layer adjacent the silver halide layer. For example, it is disclosed in U.S. Pat. No. 3,364,024 that catechol only insolubilizes gelatin at very short distances from the location at which the oxidation of the catechol occurs.
In aforementioned U.S. Pat. No. 3,364,024, there is disclosed a process for obtaining a photographic resist in a gelatin or colloid layer which is separate from and adjacent to the silver halide emulsion layer. In essence, the patentees therein found that certain oxidized developing agents are capable of "wandering" from the location at which oxidation of the developer occurs, i.e., in the silver halide emulsion layer, to a separate gelatin or colloid layer, thereby rendering same insolubilized in an imagewise manner.
In this process, however, the silver image is retained in the image pattern because a tannable or hardenable gelatin is utilized in the silver halide emulsion of the construction. To eliminate the silver from the structure, conventional bleaching and fixing steps are of course necessary. Such processing steps require additional time, require necessary additional solutions, and in addition, the silver must be recovered in two solutions, i.e., both the wash and fix solution, and is thereby difficult to be recovered therefrom.